Читать книгу Fundamentals of Aquatic Veterinary Medicine - Группа авторов - Страница 21

Intensive culture system is where animals are maintained in systems such as ponds, tanks and raceways, where the support parameters are carefully controlled and dependence on the natural environment is minimal. Such systems require a high degree of management and usually involve substantial investment and operating costs, resulting in high yields per unit area. They typically feature recirculating systems, which filter and reuse all or a portion of their water. Currently, this technique is in limited use due to its high start‐up and maintenance costs. It has several advantages, however, in that this system is highly desirable in areas where a constant water supply may be questionable or a discharge is not appropriate. Other advantages of this type of system include the ability to incorporate the growth of a second product through hydroponics and the use of settled material as fertilizer. As the technology evolves and water withdrawal and discharge requirements become more stringent, this technique is bound to see an increase in use. Ponds are also very popular for housing ornamental fish, such as koi or goldfish. Typically lined with EPDM rubber, these can be fairly simple in having only a recirculating system and waterfall or extremely complex, with sophisticated filtration and water conditioning systems.